Visual C++游戏编程基础之以范围检测碰撞

一、基本思路

1.如何检测碰撞

2.贴图的处理，因为位图底色为白色，屏蔽图与之前完全相反，如图所示

因为二进制全0表示黑色，全1表示白色，故首先将屏蔽图与背景图做OR运算，那么背景图会留下白色的部分，然后将前景图再与背景图做AND运算，最后只显示彩图；

3.用vx1、vx2的第一、二部的车速，(x1,y1)，(x2,y2)表示两辆车的贴图坐标；

二、效果

三、主要代码如下

// canvasFrame.cpp : implementation file
//

#include "stdafx.h"
#include "canvasr.h"
#include "canvasFrame.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif


// canvasFrame
IMPLEMENT_DYNCREATE(canvasFrame, CFrameWnd)//声明canvasFrame类是从CFrameWnd类派生
int vx1=5,vx2=-5,x1=-70,x2=520,y1=165,y2=150;
canvasFrame::canvasFrame()//canvasFrame()是属于canvasFrame类中的一个函数,用于贴图前的初始化
{
	Create(NULL,"绘图窗口");//Create是CFrameWnd继承而来的成员函数，用于窗口的创建和设置
	CClientDC dc(this);//类CClientDC派生于CDC，在构造时调用了Windows函数GetDC，在析构时调用了ReleaseDC。这意味着和CClientDC对象相关的设备上下文是窗口的客户区
	int width = dc.GetDeviceCaps(HORZRES);//this指向被调成员所指的对象
	int height = dc.GetDeviceCaps(VERTRES);
	GetWindowRect( &rect );
	width = ( width - ( rect.right - rect.left ))/2;
	height = (height - (rect.bottom - rect.top ))/2;
	MoveWindow( width , height , (rect.right - rect.left )/2 , (rect.bottom - rect.top )/1.5 ,true);
	GetClientRect(&rect);
	mdc = new CDC;
	mdc->CreateCompatibleDC(&dc);
	car1 = new CBitmap;
	car2 = new CBitmap;
	bomb = new CBitmap;
	car1->m_hObject = (HBITMAP)::LoadImage(NULL,"car1.bmp",IMAGE_BITMAP,196,66,LR_LOADFROMFILE);
	car2->m_hObject = (HBITMAP)::LoadImage(NULL,"car2.bmp",IMAGE_BITMAP,140,80,LR_LOADFROMFILE);
	bomb->m_hObject = (HBITMAP)::LoadImage(NULL,"bomb.bmp",IMAGE_BITMAP,187,200,LR_LOADFROMFILE);
}

canvasFrame::~canvasFrame()
{
	delete mdc;
	delete car1;
	delete car2;
	delete bomb;
}


BEGIN_MESSAGE_MAP(canvasFrame, CFrameWnd)
//{{AFX_MSG_MAP(canvasFrame)
ON_WM_TIMER()
ON_WM_CREATE()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()


// canvasFrame message handlers

void canvasFrame::OnTimer(UINT nIDEvent) 
{
	CFrameWnd::OnTimer(nIDEvent);//开始定时器计时
	CClientDC dc(this);
	mdc->SelectObject(car1);
	dc.BitBlt(x1,y1,196,66,mdc,0,0,SRCCOPY);//贴第一部车
	mdc->SelectObject(car2);
	dc.BitBlt(x2,y2,140,80,mdc,0,0,SRCCOPY);//贴第二部车
	if(x1+196>x2)//发生碰撞
	{
		mdc->SelectObject(bomb);
		dc.BitBlt(x2-100,y2,187,100,mdc,0,100,SRCPAINT);
		dc.BitBlt(x2-100,y2,187,100,mdc,0,0,SRCAND);
		KillTimer(nIDEvent);//停止计时
	}
	x1+=vx1;//未碰撞更改车的贴图位置
	x2+=vx2;
}

int canvasFrame::OnCreate(LPCREATESTRUCT lpCreateStruct) //初始化定时器
{
	if (CFrameWnd::OnCreate(lpCreateStruct) == -1)
		return -1;
	SetTimer(1,0,NULL);//这里查到不需要填入hwnd了
	return 0;
}